Improvement in dental engines



' J. B. MORRISON.

DENTAL ENGINE.

No. 111,667. Patented Feb. 7L 1871,

u N b1 i i i UNITED STATES PATENT QEEIcE.

JAMES B. MORRISON, OF ST. LOUIS, MISSOURI.

IMPRQVEMENT |N DENTAL ENGINES.

Specifica-tion forming part of Letters Patent No. 111,66?, datedFebruary 7, 1871.

."Z'o all. whom t may concern: Be it known that I, J AMES B. MORRISON,of

St. Louis, in the county of St. Louis and State of Missouri, haveinvented a certain new and useful Dental Engine, of which the followingis a specication:

The first part of my invention consists in an arran gementby which thepower from atreadle ,may be conveyed to a tool which has universalmotion, the arms being swiveled and kept extended lengthwise by springs,so as to hold the belts at au equal tension as the swivels are turned.The second part of my invention con-v pitman and the treadle, tov allowthe treadle to be readily operated in any position. The fifth part of myinvention consists inthe construction of the burr,` whose head is madeseparate and distinct from the spindle or shank, soas to admit ofreversal thereon, and of replacement when Worn out. The engine isintended chiefly for operating on teeth, and other dent-al uses.

Figure l is a perspective view of my machine. Fig.2 is a somewhatenlarged view, in elevation, of the spring-sleeve of the. pintle onwhich the head turns. Fig. 3 is a view, in elevation, of the lower partof the upwardlyextending swinging staif. Fig. 4 is a sectional view ofthe moving end of the treadle through the ball-and-socket joint. Fig. .5shows the spindle or shank and the burr detached, to exhibit theconstruction of the same.

AA is a tripod-stand, and B avertical standard xed. thereon. O is apulley,- having a crank, c, which receives a pitman, D.- At the d, andsurrounding the pitman, between this collar and the treadle, is a ring,d', of indiarubber, which acts as a spring to keep the treadle incontact with the knob E, and prevent rattling. The treadle is hinged atg to a frame, G, and the frame G is pivoted by a stud, a, upon the standA. The stud a is vertically beneath the wrist-pin c' of the crank c,when the crank stands vertically, so as to keep the treadle in theproper operating position, however much it may be' thrown around to theright or left (which may be freely done bythe foot of the operatorwithout requiring to loosen any other screw, or by other means to permitsuch adjustment.) The ball-and-Socket joint E f allows the treadle tooperate at any angle to the plane of the pulley O. His an arbor, whichis screwed fast into the standard B, and forms the journal of the pulleyC and thefulcrum-pivot of the staff 1. This arrangement allows theoscillation of the'statf I without affecting the tension of the belt J.rIlle stati' I is bent over the top of the standard B, so as to bringits upper part, I', directly over the pulley O, and the bent portion hasa vertical hole which receives a pin, t', that passes through the stati`and enters the top of the standard, to hold the, sta' in a verticalposition when desired. The lower end of the stati' I is connected to thestand by a spring, K, (see Fig. 3, where it is shown as a spring ofspiral wire,) which spring tends to raise the staff to, and to hold itin, a vertical position. The upper portion, I', of the stati' istubular, and receives the pintle L of the head M. The lower end of thepintle has a center, l, stepped in a block, N, consisting yof twocylindrical portions, the lower and smaller of which enters a spiralspring, n, by which the head is raised to preserve the equal tension ofthe belt J as the head is turned on the pintle, (which turning acts totwist the belt and depress the head.) The portion ofthe pintle L withinthe socket of the shaft I I' is enveloped in a tightitting sleeve, L',whose ends Z' are split and bent outward, so as to form springs restingagainstthe interior of the Socket, to prevent rattling. A n enlargedview of the sleeve is given in Fig. 2. The belt J passes over adouble-grooved pulley, O, whose shaft IJ has journal-bearings instandards m of the head M. The shaft I? has squared portionsp, for thereception of a grindstone or emery-wheel, p', or a chuck, 85e., and thehead has extension m', forming rests to be used in conjunction with thegrindstone, Ste. Pivoted upon tubular bosses forming portions of thejournalbearingof the shaft Pis the forked end q q of the arm Q. Theouter portion of the arm Q is tubular, and receives the pintle R. Thepintle R ends in a center, r, turning in a center socket of a slidingblock, R', similar to N, and like it thrust outward by a spiral spring,It, for a similar object, namely-preserving the equal tension of thebelt during the turning of the pintle. The pintle R ends in a fork, fr1", to which is pivoted a similar fork, t t, of an arm, T, whose squaresocket receives a square bar, U, the end of which impinges against aspiral spring, U', to keep the belt V tight. s is a beltpassing aroundthe pulley O and around the pulley S, which turns on the arbor t thatlforms the pintle of the forks lr r and t t. The

Ihar U ends in a fork, u, inwhich is journaled 'the socket-piece W, intowhich the shank w of .the burr w is inserted.

(In place of a burr any other tool, such, for instance, as a drill,` maybe used.) The socket-piece or spindle carries a pulley, W', whichreceives and is turned by the belt V, and is enveloped by a sleeve, W,which is attached to one side of the fork u, and, beside ying`iournal-bearing tothe socketed end of gives bearing to the outer end ofthe tool-shank w, and serves as A ahandle by means of which' the tool isdirected in use.

Burrs (globular tiles used by rotary motion) have heretofore been madein one piece With the shank, so that when the outer portion of the burrbecame Worn smooth, the Whole, both head and shank, was renderedworthless. I make the shank w and the burr w in separate and distinctpieces, the burr being perforated to receive the end of the shank, whichconstruct-ion admits of the inversion of the burr upon the shank whenthe outer and most-used portion becomes smooth, and also the replacement of a Worn burr by a new one When worn out, and Withoutcasting asidethe shank.

y q is an extension of one side 'of the fork q, and having an out-turnedend, q, Which comes iu contact with the standard m when the arm Q isthrown upward', and a little past the vertical, and holds the said armin a nearly vertical position.

I have explained my preferred mode of constructing the machine, but donot Wish to confine myself to the exact means shown to accomplish theresult. For instancein my experiments I have conveyed the power from thecrank-pulley C t0 the pulley W by a single belt, the vadvancing andreturning sides of which passed over separate loose pulleys at thepoints of flexnre. I have also anticipated conveying power from theshaft P to the pulley TV', or socket-piece or spindle IV, by means ofshafts turned by friction or spur gearing at the points of iexure and inthe case of friction-gears I have proposed to use an extension-jointsimilar to U U T, to keep the friction-gears in proper contact, thejournal-bearings of the gear`-shafts being connected by non-rotating butoscillating arms.

I propose in some or most cases, to envelop the moving parts, orespecially the belts, in a covering of leather or other substance.

1 I claim as my inventionl. A tool-head, as u W, having universal rotaryand eXible motion at the extremity of one or more pivoted,pulley-carrying and extensible arms, substantially as described.

2. In combination with a swiveled shaft, a spring applied s ubstantially as shown, namely, maintaining the proper extension er elongation ofthesaid shaft, and .permitting one end of it to be turned on its axis.

3. The oscillating shaft I I, turning on a center in vline With the axisof the pulley C, and connected 4to the stand by a helical or otherspring, K, substantially as and for the purpose described.

4. The treadle F, hinged to the frame G, the said frame being pivoted tothe stand,4 substantially as 'and for the purpose described.

5. The construction of the burr-tool in two separate parts, consisting,respectively, of theA perforated removable head, and spindle or shank,substantially as and for the purposes set forth.

In testimony of which invention I hereunto subscribe my name.

JAMES B. MORRISON.

Witnesses SAM. KNIGHT, STEPH. BERNAnD.

